The 2 marks look slightly different. The line crossing the A on one looks to slope at a different angle than the other - unless that's a illusion by corrosion. I'm thinking customized but prefer "unique" - you may never know. Common answer for fur trade stuff as little was documented & much was customized. Very nice find! Congrats
The MYSTERY PAGE and FUR TRADE AXES & TOMAHAWKS - FUR TRADE AXES AND TOMAHAWKS have some good info as far as how to do research, but I have not yet seen your mark. Sorry, I have limited data allotment - can't continue the search. But both of these sites look great and have LOTS of links - some might even be worth following.
Thanks for your efforts all. I suspect that It may be an A and I, l or T. The head has plenty of plowing dings so the bizzare angled slash may be from a plow. Pie in the sky guess from my limited research........Possibly North West Company stamped for the (A)thabasca trade that Peter Pond opened. Head was found about a mile from Ponds original post on the North Saskatchewan River...............All just a crude guess due to location of find................Perhaps Al...........Albany ?